Passenger seatbelt

[gavcarter]

I think my passenger seats came from a mk5 smiley, as I've added seats in the back and the mk5 and mk6 where slightly different heights I put the mk5 in front so the rear row is all the same height.
However the centre belt is slightly too short for little guys car seat. Is there an easy way to swap it for the outer belt as this one is much longer?
It looks to be all embedded in the seat and i cant see a way to get it out